This invention relates to a targeting apparatus for use in performing endofemoral osteotomy surgery. The apparatus is also suitable for conversion so that it can be used in transfemoral osteotomy surgery. In this particular surgical technique the femur is exposed along a proximal-distal line, the soft tissue (skin, muscle) being folded back on each side to expose the bone. The proximal end of the femur is now opened as a xe2x80x9cwindowxe2x80x9d and a femoral prosthesis is inserted into the bone canal.
As mentioned above, the present invention is capable of being used with both surgical approaches if converted.
There are difficulties in both techniques in assessing the particular angular position of the prosthesis in the femoral canal and the exact location of the resectioning of the femur must be accurately judged. A further difficulty arises with regard to the placement of one or more retaining bolts towards the distal end of the stem of the prosthesis. These bolts or pins pass through the bone, the stem of prosthesis and out through the other side of the bone thus anchoring the prosthesis in position. It is difficult for surgeons to judge the exact position to drill the holes in the bone to coincide with the holes in the implant and it is also necessary to select the correct angular position of the prosthesis and therefore the holes. It is also difficult for the surgeon to judge the exact distance down the femur for the holes to achieve the correct leg length of the correction.
The present invention is intended to overcome some of the difficulties referred to above and to provide apparatus which will achieve a more accurate surgical technique.
According to the present invention targeting apparatus for use in performing endofemoral osteotomy surgery comprises a support element provided with a drill guide, a connector for securing the support element to the proximal end of the prosthesis to be implanted and which include a proximal location element which is shaped to extend around the great trochanter and muscles of the femur in which the implant is to be located, and an adjustor for adjusting the angular position of the drill guide in relation to the femur about a proximal-distal axis.
Thus, the apparatus can be used to accurately locate the angular position of the drill guide and the prosthesis (anteversion setting) and which can be used to drill the holes to take the retaining bolt or bolts in the bone.
Preferably the proximal location element is in the form of a curved arm connected to the support element and this arm can be substantially S-shaped.
The proximal location element can be arranged to be detachable from the support element, for example, by use of a plug and socket connection, and this can be of a triangular cross-section.
Two detachable alternative proximal location elements can be provided, one for use with a right femur and the other for use with a left femur.
The targeting apparatus according to the invention can also be used for performing transfemoral osteotomy surgery by the provision of suitable conversion features. Thus, the apparatus can include conversion means for converting it for use in performing transfemoral osteotomy surgery.
The conversion means can include a connector for securing the support element to a resectioned femur to allow this form of surgery to be carried out.
Alternative devices are also provided for securing the support element to the prosthesis to be implanted and which is adapted to replace the shaped proximal location element.
This alternative device may comprise a substantially straight proximal arm adapted for connection to the support element.
When converted in this way the apparatus can embody the features set forth in British Patent Application Nos. 00 27698.0 filed Nov. 13, 2000, 00 27700.4 filed Nov. 13, 2000 and 01 05779.3 filed Mar. 8, 2001.
The invention also includes a kit of parts to provide targeting apparatus for use in performing endofemoral and/or transfemoral osteotomy surgery comprising a support element provided with a drill guide, a connector for securing the support element to a prosthesis to be implanted when performing endofemoral surgery and which includes a proximal location element which is shaped to extend around the great trochanter and muscles of the femur, alternative connectors for securing the support element to a prosthesis to be implanted when performing transfemoral surgery, an adjuster for adjusting the angular position of the drill guide in relation to the resectioned femur about a proximal/distal axis, and a connector for securing the support element to a femur.
The kit of parts can also include a drill guide element which has a line of drill guide openings each of which is adapted to guide a drill and a connector for rigidly securing the drill guide element to the connector for securing the support element to a femur.
Also included in the kit of parts can be a drill guide for drilling openings through the bone and soft tissue when it has been folded back into position at the proximal end of the femur when conducting the transfemoral surgery.